Sedimentation device



July 20, 1937. c, SCOTT 2,087,725

SEDIMENTATION DEVICE Filed Dec. 22, 1934 4 Sheets-Sheet l INVENTORCHARLES H. SCOTT ATTORNEY.

July 20, 1937. c. H. scoTT 2,087,725

SEDIMENTATION DEVICE Filed Dec. 22 1954v 4 She ets-Sheet 2 Pie-.2.

INVENTOR 24- ATTORNEY.

RLES Ascorr; y V

July 20, '1937. c. H. sco'r'r SEDIMENTATION DEVICE 4 Sheets-Sheet 3Filed Dec. '22, 1934 -m u n mm \m mm. w mm km mm Q INVENTOR CHARLES H.SCOTT ATTORNEY.

July 20, 1937. c. H. scoTT SEDIMENTATION DEVICE Filed Dec. 22, 19:54 4Sheetg-Sheet 4 INVENTOR CHARLES H. SCOTT mmww ATTORNEY.

Patented July 20, 1937 UNITED STATES SEDIMEN'IATION DEVICE Charles H.Scott, Queens Village, N. Y., assignor to The Dorr Company, Inc, NewYork, N. Y., a corporation of Delaware Application December 22, 1934,Serial No. 758,720

12 Claims.

This invention relates to sedimentation apparatus of the typeexemplified by thickeners and clarifiers, wherein solids suspended inliquid settle to the bottom of a tank by sedimentation to form a sludgewhich is raked to a sludge discharge. Commonly this discharge iscentrally located and the rake blades are arranged to depend frommembers propelled by a rotatable vertical support.

An object of the invention is the provision of sedimentation apparatuswhich is simple of construction, which is efiective and efficient inoperation, and which will have long life. A more specific object is theprovision of an improved supporting and driving means for the rakingmembers used in such apparatus. A further object is to providesedimentation apparatus which will operate with a particularly low powerconsumptlon,-for which the vertical space requirements will be small,and which will present a sightly appearance. Other objects of theinvention will in part be obvious and will in part appear hereafter.

With the foregoing and other ends in view the invention includes amongits various features the provision of means whereby the rakes of athickener, clarifier, or the like, may be firmly and securely supportedby compactly arranged means and for intermittent or continuous travelover considerable periods of time without substantial wear on thebearing surfaces and with a maximum of efficiency and effectiveness. Inaccordance with the invention the rake-supporting means includes arotatable vertical shaft provided with supporting means disposedhorizontally of the shaft and a considerable distance outwardly of thenormal center of gravity of the rake members. Such means may include anoutwardly-extending member on the upper part of the shaft and means torotatively support this outwardly extending member adjacent to itsperiphery so that the points of support may be well spread out.Accordingly normal tendencies of e the shaft to tip are counteracted,and at the same time there is provided an effective and shallow supportwhich avoids the necessity of submerged bearings for the shaft or ofunsightly and spaceconsuming elevated braces. As will be apparent, wheresubmerged bearings for the shaft are employed the wear on these hearingsand on the shaft is considerable, and a large frictional resistance tothe drive is set up with consequent heavy'loss of power. Elevatedbraces, besides being unsightly, increase the fire hazards when made ofwood, and require a large amount of head room which prevents theinstallation of clariflers, thickeners, and the like, in a variety ofotherwise desirable locations. Another feature of the invention is thesupport of the shaft on bearings which are surrounded by alubricantretaining chamber, so that the shaft and its associatedmechanism will rotate freely at all times.

In its more specific aspects the invention contemplates the inclusion ofthe drive gearing for the shaft within the lubricant retaining chamber.In devices of the character under consideration moreover, it is ofconsiderable importance that effective resistance be provided forextraordinary I the shaft vertical at all times. By the arrange-f mentof such means above a portion of the outwardly-extending means so thatit will oppose upward movement of the periphery of the latter atsubstantially all points thereabout, assurance is had that nosubstantial-tipping movement of the shaft in any direction can occur.The formation of this means as a part of the lubricant-retaining chamberis particularly advantageous, in that, even when the outwardly-extendingmember contacts with such means, the frictional drag will be small. Afurther feature of the invention resides in the provision of an overloadrelease mechanism which includes particularly simple and effectivecentering means for the spring thereof and also includes means toprevent separation of the parts.

. While the present invention in various of its aspects is applicable tosedimentation devices of a variety of types, it is exemplified asembodied in a cla'rifier of a character utilizable in sewage disposalplants. It is particularly noted, howliquids or liquid-solids mixtureswherein thereis included a tank having a rotatable shaft or.

support extending downwardly thereinto and carrying suspended weightsuch as outwardly extending arms serving as raking elements orotherwise. In sedimentation devices it is customary to provide a tankll, including a side wall l2 and a bottom l3, for holding the liquidfrom which solids in suspension are to be removed. Solids settling tothe bottom I3 take the form of sludge or of pulp which is raked orimpelled by slowly moving rakes I t toward a central bottom dischargehopper |5 from which the sludge or other thickenedproduct is removedthrough a discharge pipe 56. The rakes ordinarily comprise blades 11carried on rake arms 98 which extend more or less radially from acentral rotatable support.

In accordance with an embodiment of the present invention the support isin the form of a vertical shaft 19 which is in turn supported adjacentto its upper end by an outwardly extending member in the form of aspider 20. The spider rides on suitable bearings such as ball bearings2| carried on a horizontally disposed bearing race 22 at points spacedoutwardly a sufficient amount so that ordinary variations in the weightof the sludge at different sides of the tank will not tip the shaft tolift the spider ofi its support at one side. The race 22 is providedwith an annulus 23 supported by a framework 24 which extends across thetop of the tank. As exemplified, the spider is formed with peripheralteeth providing an external gear 25 which meshes with a worm 26 carriedon a countershaft 21. The counter-shaft is driven by means of a chain 28from a shaft 29, which in turn is driven by an electric motor 30supported in proximity to the spider on the framework 24.

The vertical shaft I9 is entirely carried from, turnably supported byand maintained in proper aligned position solely through the medium ofan outwardly extending spider member 20 which is mounted so as to turnabout a vertically extending axis which is the maintained vertical axisof the shaft. In other words, all guiding and'supporting of the shaft isthrough the medium of the outwardly extending spider. This spiderprovides or constitutes a part of the construction which is sometimesreferred to as the horizontally-turnable upper main bearing member.

An underlying construction constitutes a carrying means for rotatablysupporting the outwardly extending spider member. Said carrying meanscomprises a member or part that provides the horizontally-disposedbearing race 22 and provides that which is sometimes referred to as astationary lower main bearing member. This lowerbearing member providesa horizontally-extending annular supporting-bearing surface portionconstituting a lower carrying section which is the horizontally-disposedsection that is referred to as the bearing race 22.

The spider member 20 has at the underside thereof an annularsupported-bearing surface portion sometimes referred to as an uppercarried section that corresponds to and overlies the annularsupporting-bearing surface portion of the lower main bearing member.

From that which has preceded, it will be seen that the spider isturnably supported in respect to the lower bearing member through themedium of a series of rollable members or elements in the form of balls.This series of balls may beviewed as collectively constituting anannular intermediate-bearing means of a type to lessen friction and toavoid excessive wear as between the supporting and supported bearingsurface portions. This intermediate bearing element is disposed betweenand along the annular sections respectively constituting said lowercarrying and upper carried main-bearing surface portions and thereforethe spider derives support from several horizontally-disposed sectionswhereby as the spider is caused to turn about its vertically extendingaxis it is at all times properly positioned for effecting the desiredturning movement of the shaft about its vertical axis.

In order to ensure the preventing or avoiding of any objectionabletilting of the spider and therefore avoid any objectionable tilting ofthe shaft from its vertical alignment and whereby the parts carried bythe shaft will at all times be properly positioned in respect to therest of the tank structure an annular cover member 33 hereinafterreferred to has been provided as an important part of a tilt-restrainingconstruction which may be viewed as embodied in the hearing structure asa whole. The lower bearing member that provides the raceway 22 and theseries of balls constituting the intermediate bearing element may becollectively viewed as providing the carrying means for rotatablysupporting the outwardly extending spider member 22. This carrying meansis supported from a stationary means which has fixed relationship inrespect to the tank and which is provided by the fixed structuralframework 24.

To insure that the spider will rotate with a minimum of friction thereis provided a flange 3| extending outwardly from the member 23 andupwardly beyond the bearing race so as to provide a chamber for theretention of lubricant adjacent to the bearings. The bearingsaccordingly run in lubricant at all times so that friction and the unitpressure on any moving surface are reduced. In order to assure theretention of the lubricant, a packing 28' is provided to seal the spacebetween the spider 20 and the annular member 23. In the present instancea portion 32 of the flange 3| extends above the worm I 8 so as to retainthe lubricant adjacent to the gear and worm. An annular cover member 33is provided to close the lubricant chamber, a supplementary cover 34being provided above the worm. There is thus provided a' simplyconstructed lubricant chamber whereby assur-.

ance is had that the bearings and gearing will perform their heavy workwith a minimum of friction and consequent wear. The shaft hangs freelyfrom the spider and has no contact with any stationary member, thuspreserving the shaft from wear.

As will be observed, the bearings provide a support for the shaft whichis well spaced outwardly thereof so that tendencies of the shaft to tipwhen the rakes encounter particularly heavy materials on one side of theshaft will be minimized. In order however to insure against tipping ofthe shaft regardless of the conditions of operation, the cover member 33is provided with an annular portion 35 extending in close proximity tothe annular rim or bead 36 extended above the upper surface of the rimof the spider, so that the spider is held down on any side at which itwould tend to rise under unbalanced conditions, and the shaft ismaintained in a vertical position. As will be apparent, the lubricant inthe lubricant retaining chamber will work its way between the portions35 and 36, so that even when the surface 36 bears against the surface 35there will be no large frictional drag.

In the present instance the shaft I9 is mounted on the spider forlongitudinal movement to permit the adjustment of the height of therakes.

Asexemplified the shaft is formed with a keyway 31 into which'a key '38in the spider fits, and the shaft extends through a bore 39 in thespider. The bore is provided with a grease chamber 40. Normally thedownward movement of the shaft is positively limited by a pin 4|extending through the shaft and above the central portion of the spider.The shaft carries a threaded upright 42 which runs through an interiorlythreaded sleeve 43, rotatably carried on bracket 44 extending upwardlyfrom the spider. The sleeve 43 is provided with a hand wheel 45. Byoperation of the hand wheel the shaft may be lifted through the bore tolift the rakes [4 when desired. In order to insure against splashworking into the bore 39 the spider carries a depending sleeve 40' whichsurrounds the upper portion of the shaft.

In order to prevent excessive load from harming the mechanism, the worm25 is slidably mounted so that in case of overload it may move forwardlyagainst the pressure of a spring, in stead of rotating the spider. Atthe end of the countershaft 21 remote from the driving chain 28 there isprovided a thrust bearing 41 and a bracket head 48. The countershaftrotates within a sleeve 49, and the space between this sleeve and thebracket head is sealed by means of the packing 50 so as to retain alubricant. The bracket head is formed with a recess into which asemi-spherical nub 52 on a spring head 53 closely fits, the recess beingconformed to the surface of the nub. A coil spring 54 bears against thehead and against a stationary head 55 on the other side. A pair of rods55 extend from the head 55 into the head 53. When the load on the rakesbecomes excessive, the worm moves forwardly through the sleeve 49 andcompresses the spring, the portions 5! and 52 serving to keep the springpressure centered. A suitable alarm device may be provided if desired. Acollar 51 onthe countershaft 21 prevents the countershaft.

from slipping rearwardly, so as to assure that the thrust bearing 41will not slip out of place even when there is no load on the mechanism.

Liquid to be treated by the device may be introduced into the tankthrough a launder 55 and feedwell 59 and liquid from which suspendedsolids have settled passes out through an eflluent launder 50 and outlet5|.

Operation The motor drives the countershaft through the medium of'the,shaft 29 and the chain 28. The worm on the countershaft rotates thespider and shaft l9 and causes the rakes to move slowly about the lowerportion of the tank so as to cause the settled solids in the form ofpulp or sludge to be moved toward the discharge hopper l5. The provisionof the horizontally disposed support for the shaft mounts the shaftsteadily without submerged or elevated bearing members. The spiderrotates smoothly on its lubricated bearings and smoothly carries theheavy weight of the rakes. If a tendency of theheavy sediment on oneside of the tank to tip the shaft is sufliciently great to lift thespider off the bearings at one side, the rim of the spider will bearagainst the cover 33, with the result that no substantial tipping of theshaft can even then occur. Since the rim of the spider is lubricatedthere will be no large added frictional drag. If there is an excessive.load on the rakes, the spring 54"serves to provide a release withoutthrowing. the

countershaft off-center, or causing an off-centerthrust on the thrustbearing 41. This bearing,

moreover, will never be released; even if the worm is rotated backwards,due to the provision of the collar 51. v

The following paragraph is herewith included by way of broadillustration and not by way of specfic limitation whereby the purport ofthe language as employed in certain of the claims will be rendered moreclear and definte.

7 It will be manifest that reversal of parts or substitution ofmechanical equivalents can be ripheral portion of the bearing member23Iis U-shaped whereby there results an on holding or receiving pocketwhich can be relied upon for holding a lubricating medium formaintaining constant lubrication of the gear and the antifriction balls2| constituting one form of rollable members. The rotation of the ballsconsequently effects lubrication of the parts engaged thereby.

The stationary bearing member 23 is carried by astructure which may be,referred to as a bearing supporting structure or bearing supportingconstruction which is fixed in relation to the sedimentation tank orbasin.

An upper member which extends to and over the stationary bearing memberis embodied by a spider shaped member 20 provided at the undersidethereof with an annular .raceway or race defining portion that isoperatively positioned on and in engagement'with the anti-friction ballsor rollable members 2 I. The member which provides this spider 20 isherein referred to as the horizontally turnable bearing member and itembodies or has at the periphery thereof a driven annular-gear in theform of an external worm driven gear 25. This gear dips into the oil oras otherwise expressed, into the oil receiving pocket of the stationarybearing member. The stationary bearing member has or is provided withbearings for receiving a shaft 21 that in turn carries and drives apowertransmission gear in the form of a worm. 25 which has driving engagementwith the annular gear 25. This worm gear 25 may be viewed as a powertransmission gear constituting part of a speed reducing and powertransmission mechanism and it is prefferring of sedimented solids fromdiverse sections of the tank bottom to a settled solids dischargeprovided by a central bottom discharge hopper l5 and the discharge pipeI5 leading therefrom.

A unit embodying the present invention has as an important function thesedimentation or settling of solids from the liquid solids mixturewhereby there is required the raking of the sedimented'solids to efiectdisposal thereof from the bottom of the tank or basin while at the sametime there is generally carried out a withdrawal of supernatant liquidfrom the upper interior portion thereof as through the medium of aneffluent peripheral launder provided at 60 and which is sometimesreferred to as a part of the supernatant liquid withdrawal means.

The rake carrying structure is normally turned so as to rotate inhorizontal paths about a vertical axis common to the raceways of thestationary and turnable bearing members and it is important in certaininstallations to maintain this depending structure against tilting. Tothat end as has been indicated above, there is provided an anti-tiltingdevice extending from one of said bearing members towards and inoverlapping relationship in respect to the other bearing member. In theembodiment shown this anti-tilting member is provided by an annularcover plate which is secured to the upper end of the outer leg of theU-shaped section. The cover plate extends inwardly over the oil pocketor oil holding portion and ultimately to and over and in overlappingrelationship with respect to the turnable bearing member whereby thelatter is prevented from tilting, or as otherwise expressed, from upwarddisplacement to any substantial extent with respect to the stationary,

bearing member with which it is associated. This cover member functionsnot merely as an anti-tilting element, but it extends over the oilpocket; it serves as a cover protecting the oil pocket againstentranceof dirt, water, or other foreign substances and it also provides aprotective zone within which the driven annular gear and the worm orpower transmission gear driving it functions under encased andprotective conditions. Due to the U-shaped section an annular oilreceiving section or pocket has been provided within which the ballraceways are located at an elevation below that of any oil overflowlimit as determined by any upper edge of the upstanding legs of theU-shaped portion. The annular worm driven gear and the powertransmission gear orworm extend into the oil receiving or pocketsection. It will therefore be borne in mind that the anti-friction ballsand the raceway portions engaged thereby, as well as any and all gearelements that extend into the oil receiving portion are constantlylubricated as the apparatus functions.

It will thus be seen that there is provided a simple, strong, smoothrunning, and sightly construction, which combines efliciency an'deffectiveness with long life.

Since certain changes may be made in the above construction anddifferent embodiments could be made without departing from the scope ofthe invention, it is intended that all matter contained in the abovedescription or shown in the accompanying drawings shall be interpretedas illustrative and not in a limiting sense.

I claim:

1. Sedimentation apparatus comprising a tank having a centrally locatedsettled-solids discharge portion in its bottom, a shaft extendingdownwardly into the tank, travelling rakes deriving their support fromsaid shaft and adapted to move settled solids toward said dischargeportion, an outwardly extending member connected with said shaftadjacent to its upper end and serving to support the same, a bearingrace, bearings in said race for rotatively supporting said outwardlyextending member at outwardly spaced points whereby a horizontallyextended supportfor the shaft and rakes is provided, means to supportsaid race, and means extending above and engaging with an outwardlydisposed portion of said outwardly extending member positivelyto preventsubstantial tipping of the shaft, said shaft being unconfined at allpoints beneath'said out wardly extending member.

2. Sedimentation apparatus comprising. a tank having a settled-solidsdischarge portion, a shaft extending downwardly into the tank,travelling rakes deriving their support from said shaft and adapted tomove settledvsolids toward said discharge portion, an outwardlyextending member connected with said shaft adjacent to its upper end andserving to support the same, said outwardly extending member beingformed to provide an external gear, a worm meshing with said gear, meansto drive said Worm, a bearing race, bearings in said race adapted tosupportsaid outwardly extending member at horizontally disposed points,means disposed interiorly of said bearings providing an annular packingadjacent to said outwardly extending member, a wall extending outwardlyand upwardly from said bearmg race and about said gear and worm, andcover means extending from said wall over said gear and in proximity toan upper annular portion of the outwardly extending member to preventsaid' shaft from tipping when there are unbalanced conditions in saidtank and to provide with said wall a lubricant retaining chamberenclosing said bearings and said gear and worm. j

3. Sedimentation apparatus comprising a tank having a settled solidsdischarge portion, a shaft extending downwardly into the tank,travelling rakes deriving their support from said shaft and adapted tomove settled solids towards said discharge portion, an outwardlyextending member connected with said shaft adjacent to its upper end andserving to support the same, a bearing race, bearings in said race forrotatively supporting said outwardly extending member at outwardlyspaced points whereby a horizontally ex' tended support for the shaftand rakes is provided, and means extendingoutwardly and upwardly fromsaid bearing race and inwardly above the periphery of said outwardlyextending member and completely enclosing the periphery of the same,said means being in sealed relationship with said outwardly extendingmember and constituting an annular chamber for retaining a lubricant.

4. A sedimentation unit comprising a tank provided with supernatantliquid and settled solids discharge outlets respectively leading fromthe upper and lower portions of the tank; a bearing support constructionfixedly positioned in respect to the tank; a stationary bearing memberhaving a horizontally extending annular raceway carried by said supportconstruction; a turnable bearing member having an annular racewayoperatively disposed above and in respect to the raceway of thestationary bearing member; a series of anti-friction rollable elementsoperatively disposed between said raceways and serving as means by whichthe turnable bearing member derives support from the stationary bearingmember; sedimented solids raking elements disposed over the bottom ofthe tank and functioning incident to the turning of the same about thevertically extending axis that is common to the raceways to effect animpelling and transferring of sedimented solids from the diversesections of the tank bottom toward and ultimately to said settled solidsdischarge outlet; a rake carrying structure depending from said turnablebearing member and in turn carrying said raking elements; means forimparting horizontal rotary movement to the turnable bearing member andassociated members carried thereby; and a tiltre'straining meanscomprising a rigid construction secured to one of said bearing membersand in overlapping relationship with respect to the other of saidbearing members on the opposite side of the raceway from the side towhich it is fixed so as to prevent any substantial movement of theturnable bearing member from its normal operative relationship inrespect to the stationary bearing member.

5. A sedimentation unit as defined in and by claim 4 in which theturnable bearing member is provided with an annular driven gear at 'theperiphery thereof and in which the tilt-restraining means includes aflange extending outwardly and upwardly from the stationary bearing and.an annular cover connected to said flange and extending inwardlytherefrom to andin overlapping relationship with respect to the turnablebearing member closely adjacent thereto.

6. A sedimentation apparatus having a tank for receiving liquid to besubjected'to sedimentation provided with supernatant liquid withdrawalmeans leading from the upper portion of the tank and a settled solidsdischarge outlet leading from the lower portion of the tank; a bearingsupport constructionflxedly positioned in respect to the tank; astationary bearing member having a horizontally extending annularraceway carried by and affixed to said support construction; a turnablebearing member having an annular raceway that is operatively disposedabove and in respect to the raceway of the stationary bearing member; aseries of anti-friction rollable elements operatively dlsposedbetweensaid raceways and serving as a means by which the turnable bearingmember derives support from the stationary bearing member; sedimentedsolids raking elements operatively disposed over and in relation to thebottom of the tank and said raking elements and means forimpartingrotary movement to the turnable bearing member and associated memberscarried thereby; which apparatus is characterized in that the stationarybearing member has an annular portion which is U-shaped in cross sectionto provide an annular oil pocket, in that the raceway of said stationarybearing member is at an elevation below that of any oil overflow limitas cludes a driven gear wheel provided on and as a part of the turnablebearing memberand a power transmitting and speed reducing gear mechanismthat comprehends a power transmission gear element supported in bearingsprovided on and by the stationary bearing member and which is in drivingengagement with said driven gear wheel for imparting rotary move ment tothe latter and therethrough to the turnable bearing member and the partscarried thereby, and in that there is included as a part of thetilt-restraining means an annular cover member which extends over saidpower transmission gear element to and past the toothed section of saiddriven gear wheel.

8. Apparatus for treating liquids and liquidsolids mixtures comprising atank having an inlet for the material to be treated and an outlet forthe discharge of treated material, a shaft ex' tending downwardly intothe tank, travelling arms deriving their support from said shaft andextending outwardly therefrom, an outwardly extending member connectedwith said shaft adjacent to its upper end and serving to support thesame, a bearing race, hearings in said race for rotatably supportingsaid outwardly extending member. at outwardly spaced points whereby ahorizontally extended support for the shaft and arms is provided, meansfixed in relation to the tank to rigidly support said race, and meansextending above andengaging with an outwardly disposed portion-of saidoutwardly extending member and rigidly flxed with respect to the meansto support the bearing race positively to prevent substantial tipping ofthe shaft.

9. Apparatus for treating liquids and liquidsolids mixtures-comprising atank having an inlet for material to be treated and an outlet for thedischarge of treated material, a shaft extending downwardly into thetank, travelling arms deriving their support from said shaft andextending outwardly therefrom, an outwardly extending member connectedwith said shaft adjacent to its upper end and serving to support thesame, said outwardly extending member being formed to provide anexternal gear, a worm meshing with said gear, means to drive said worm,a bearing race, bearings in said race adapted to support said outwardlyextending member at horizontally disposed points, means fixed inrelation to the tank to rigidly support said race, means disposedinteriorly of said bearings providing an annular packing adjacent tosaid outwardly extending member, a wall extending outwardly and upwardlyfrom said bearing race and about said gear and worm, and cover meansextending from said wall over said gear and in proximity to an upperannular portion of the outwardly extending member to prevent said shaftfrom. tipping when there are unbalanced conditions in said tank and toprovide with said wall a lubricant retaining chamber enclosing saidbearings and said gear and worm.

10. Apparatus for treating liquids and liquidsolids mixtures comprisinga tank having an inlet for material to be treated and an outlet for thedischarge of. treated material, a shaft extending downwardly into thetank, travelling arms deriving their support from said shaft andextending outwardly therefrom, an outwardly extending member connectedwith said shaft adjacent to its upper end and serving to support thesame, a bearing race, bearings in said race for rotatably supportingsaid outwardly extending member at outwardly spaced points whereby ahorizontally extended support for the shaft and arms is provided, andmeans extending outwardly and upwardly from said bearing race andinwardly above the periphery of said outwardly extending member andcompletely enclosing the periphery of the same, the inwardly-extendingportion of said means being in closely spaced relationship with saidoutwardly extending member and constituting an annular chamber forretaining a lubricant.

11. Apparatus for treating liquids and liquid- -solids mixturescomprising a tank having an inlet for the material to be treated and anoutlet for the discharge of treated material, a shaft extendingdownwardly into the tank, travelling arms deriving their support fromsaid shaft and extending outwardly therefrom, an outwardlyextendingmember connected with said shaft adjacent its upper end and serving tosupport the said shaft, carrying means engaging the under surface ofsaid outwardly extending member adjacent its periphery for rotatablysupporting said outwardly-extending member substantially at thecircumferential portion thereof whereby a horizontal support is providedfor the outwardlyextending member and for the .shaft and arms supportedtherefrom, stationary means by which said carrying means is rigidlysupported with respect to the tank, and tilt-restraining means fixedagainst vertical movement with respect to the tank and extending aboveand engaging with a portion of said outwardly-extending memberpositively to prevent substantial tipping of the shaft.

12. Apparatus for treating liquids and liquidsolids mixtures, comprisinga tank having an inlet for material to be treated and an outlet for thearms about a vertically-extending axis that is common to the aforesaidannular surface portions; an arm-carrying structure depending andderiving support from the turnable bearing member and in turn carryingsaid outwardly-extending arm; means for imparting horizontal rotarymovement to the tumable bearing mem- 4 ber and associated memberscarried thereby; and a tilt-restraining means comprising a rigidconstruction secured to one of said bearing members and extendingtherefrom into overlapping relationship with respect to and adjacent theother of said bearing members so as to prevent any substantialmovement'of the turnable bearing member from its normal operatingrelationship in respect to the stationary bearing member.

CHARLES H. SCO'I'I'.

